The Red Cell Gordon Conference has provided an informal atmosphere for in depth discussions on topics related to red cell biology, regulation of erythroid gene expression, hematopoiesis, and clinically related issues. The meeting, which is consistently oversubscribed, draws leading scientists and clinicians from around the world. The 1999 meeting should be especially noteworthy, given the major recent advances in several of the prominent areas. Nine individual sessions are planned, each featuring a short introductory lecture, three full lectures, and several short talks chosen from the submitted Abstracts and devoted primarily to late-breaking discoveries of major significance. A new component of this Gordon Conference will be a 10 min collective brain-storming period at the end of each session, where conferees will be encouraged to identify the major unanswered questions in the field. The session topics are: 1. The knock out/null phenotype of RBCM proteins. 2. Spectrin and membrane mechanics. 3. Erythroid gene regulation I: LCR Function and Higher-Order Gene Organization. 4. Erythroid gene regulation II: Regulation of Transcription within the Globin Gene Locus. 5. O2, NO, and Fe+3 in RBC biology. 6. Erythrocyte proteins in nonerythroid cells. 7. Hematopoiesis I: Origin of stem cells and lineage commitment in mammalian systems. 8. Hematopoiesis II: Origin of stem cells and lineage commitment in nonmammalian vertebrates. 9. Interactions between red cells and other cells. Two afternoon poster sessions will also feature a mixture of presentations from all disciplines. The diversity of scientific approaches/interests combined with the richness of discussions of previous Red Cell Gordon Conferences has led to numerous productive collaborations and fostered new developments in these important areas of basic and clinical research.